custom shortcode to insert javascript

functions.php

// insert javascript into WordPress posts or popups
// use shortcode [wpp_insert]
add_shortcode( 'wpp_insert', 'wpp_insert_code' ); 
function wpp_insert_code() { 
  ob_start(); 
  ?> 
  <!-- paste your html and javascript here --> 
  <?php 
  $html = ob_get_clean(); 
  return $html; 
}